INSECT PESTS

Gisborne Times, Volume LXXIII, Issue 11951, 23 May 1933, Page 3

INSECT PESTS

NEARLY 'ALL .IMPORTED/ / NEW ZEALAND .UNPROTECTED. WHITE BUTTERFLY MENACE. . “Of the.destructive- insects in New Zealand about. 78 per cent. • have been introduced,” said ;Dr,i D. :Miller, entomologist, .of. the Oawthron. Institute-, in an address t° the Wellington Philosophical Society. > “Tho expansion of world transport, with its resultant spfeqd destructive insects, has ltd the. more enlightened countries to establish a rigid system of quarantine and port inspection against invasion by uiittesii’ablo insects and diseases. . In New Zealand, where, perhaps. W° aro lulled into a position of false security..by our geographic, isolation, which is 110 longer an isolation, or where perhaps scientific .opinion, "though hacked by omplo evidence, is- meeting the-samp blind opposition as did Lord Lister,in hi s advocation--of antiseptics, no effective steps are taken .-to protect:the Dominion ' from any - insect scourges yet to; comb "to our .shores. , “A most > spectacular example, which has drawn, to .it more universal public attention than any other insect in the history of this country, is the cabbage- whitd-luittorJly which within three years-of its mvpcnranec at Napier had spread throughout most' (if the North Island. Tf there had 'been-an efficient quarantine -service this insect would never have had the op port uni tv o f overspreading the country as ’t has done. The destructive potentialities of the butterfly aro enormous, and n extensive attacks; are- made- upon- the turnip and ra.po crops of the Dominion, then the situation will he very serious, especially in regard to the dairying and sheep industries. PORT INSPECTION- INADEQUATE. ‘T have frequently stressed that tho question of an adequate quarantine and inspection service in. New Zealand is a matter for urgent attention. At-pre-sont wo have -a system of port - inspection totally unfitted for modern requirements. Wo lag behind in this imps; riant branch ofplant protection. Wo may liken our position to .that of a well-provisioned hut under-garrisoned fort iwher© civilians fmd shelter; hut though teetion of the cviilians from tho enemies that hare managed to gain ,a footing, is left to the framed rn, 1 . 1s <m, the duty of repelling ‘-irther. invasions has been placed- in tile hands of the untrained civilians. I am not criticising the men in charge of our present system: T condemn the system itself as practically useless. ‘ “Most of tho outstanding and widely established insect posts in practically all countries have been introduced usually prior to the i!M.figuration of an efficient quarantine, and on sorvi op.' j'ORESTS EXPOSED TO SCOURGES. “Th|3 forests of the world/- - continued Dr. Miller, “are subject to serious insect invasions; thp bark-lrectlcs alone in the. United States destroyed trees .at .£2OO 000,00.0 during -a period of o 0 years'. In New Zealand, though we may congratulate sour selves on having to contend with only a few forest pests, any day may .see our extensive exotic plantations laid waste by any one of the most destructive scourges that lia-s yet t-o reach om sh-oies, Ye have no organisation to prevent an invasion ; neither have we now sufficient trained men to handle such a situation ; our forests and plantations are exposed to the will of any pest that care s to enter them. We had built u n in Now Zealand a most efficientservice in the Forest Biological Research Station, especially for the protection of our forests, hut this,- ' 11V iko sc-called interests of economy, has been virtually wiped out! “An illustration of what is likely to befall us is found in the history of the larch saw-fly. This European inject became established in the east- ' ern States of North America, where it destroyed 38-t,Coo,oooac. of larch; after some years the pest was controlled by an effective parasite. Rut what eh an co would our half-million acres of pine trees stand in the- face of a similar invasion?”

WHITE BUTTERFLY

SKULL AS CHEMIST. Washington, April id

Butterflies are often expert chemists, :vir. Austin 11. Clan;, biologist oc too Smithsonian Institution, Aias discovered. Thu outstanding example of tht winged chemists, Mr. Clark sajs, i s the cabbage butterlly, a smaii etcaiuro -with chalky wings which was introduced into the ' United States from Europe in the middle of the last CjJJltury. It lias become quite common throughout the I-ast, especially in the neighborhood of cabbage patches. > The female lays her eggs on cabbage and other related plants because they contain the appropriate chemical constituents for the young."When brought to the now world, the insect began laying eggs on the leaves of the garden nasturtium, a plant which happens to contain about the same chemical constituents a,s the cabbage, although, botanically there is no relationship and the appearance is very different. , How does tbo cabbage butterfly know that the nasturtium is one of the few plants outside the cabbage family upon which _ the caterpillars could hope to survive. ? “Most caterpillars,” sa ys Mr. Clark, “are able to subsist <®ly on a very limited number of plants which are closely related to oach other in their chemical composition. A good example is afforded- by the, various fritillaries which feed almost exclusively on violets. T" r o varieties live entirely on the haekbe-rry tree. “The ancestors of. tbo cabbage butterfly,” Mr. Clark says; “at least for thousands of generations, , cculcl. not have known the nasturtium,' yet it was unerringly selected, ,f